In a typical wireless network, many devices can enter an area serviced by a wireless controller and communications can be set up between the devices and the controller. Thus, a significant overhead is required for a device to “join” a network. To facilitate an efficient set up between multiple networkable devices, communications must be effectively configured and managed. Thus, a typical wireless network has a communications coordinator/controller such as an access point, a piconet controller (PNC), or a station that configures and manages network communications. After a device connects with the controller, the device can access other networks such as the Internet. A PNC can be defined generally as a controller that shares a physical channel with one or more devices, such as a personal computer (PC) or a personal digital assistant (PDA), where communications between the PNC and devices form a network.
The Federal Communications Commission (FCC) limits the amount of power that network devices can emit during transmissions. Due to the number of networks, crowded airways, requirements to accommodate more devices and low power requirements, new wireless network standards continue to be developed. Accordingly, there has been a lot of activity to develop low power network communications in the 60 GHz range utilizing directional communications with millimeter waves. An omni-directional transmission or communications different from a directional communications/transmission generally provide a single antenna point source radiation pattern where the signal energy propagates evenly in a spherical manner unless obstructed by an object. In contrast, in directional communications the signal from a transmitter and a receiver sensitivity can be projected or focused in a particular direction. With such high frequency low power signals, directional transmissions or beams that can project communications in the direction of the receiving entity are advantageous and important. Likewise, receive systems that can steer receive sensitivity in particular direction (i.e. the direction of where the transmission originates) are very important and advantageous. It can be appreciated that traditional omni-directional transmissions/communication systems cannot provide reliable low power, high data rate communications at distances of over a few meters. Generally, directional antennas or antenna arrays can provide gains that are much higher than omni-directional antennas by forming a narrower beam that focuses radio frequency power towards the receiving system. Likewise, a receiver can focus it's receive sensitivity in a particular direction. Thus, a transmitter can focus signal energy in the direction of the desired receiver and a receiver can focus it's receive sensitivity in the direction of the transmitting source to provide an efficient system.
A directional transmission system can provide improved performance over omni-directional systems due to the increased signal strengths between devices and decreased interference from devices transmitting from directions where the receiver is less sensitive. Higher data rates, on the order of a few Gigabits per second, are possible in a directional transmission mode since the directional link employs directional antennas and benefits from higher antenna gains. However, these directional systems are typically more complex, slower and more expensive than traditional omni-directional transmission systems. After the association and beam calibration process, efficient data exchange between the device, the controller and other networks such as the Internet can occur.
It can be appreciated that many network environments, such as offices, office buildings, airports, etc., are becoming congested at network frequencies as many devices enter a network, exit the network and move in relation to the controller of the network. Setting up directional communication and tracking movement of devices in traditional systems requires a relatively long, inefficient association time and set up time for each device. Such continued increase in the number of users for an individual network continues to create significant problems.